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In the cold regions of China, the existing rural houses are widely distributed and in large numbers. There are widespread problems such as low thermal performance of building envelopes, high building energy consumption, and poor indoor thermal environments. Reducing the energy consumption of building heating by reforming the envelope structure can reduce the environmental pollution caused by heating. In this paper, the existing rural houses in Tongchuan City, Shaanxi Province are taken as the research object, and EnergyPlus software is used to calculate building heating energy consumption, and the schemes are compared and selected via the entropy value method. Based on a comprehensive benefit evaluation, the best scheme for the renovation of building envelopes of rural houses in Tongchuan City is put forward. The research results show that the energy saving rate of buildings can reach more than 50% after renovation. In the evaluation of energy saving, incremental cost, return on investment, carbon emission reduction and unguaranteed hours, the weights are 0.1915, 0.2104, 0.2312, 1755, and 0.187, respectively. The best renovation scheme for rural housing is as follows: the thickness of the XPS board is 90 mm for exterior wall insulation; the thickness of the XPS board is 80 mm for roof insulation; the window-to-wall ratio of additional sunspace is 0.6; and the type of exterior windows is a broken-bridge hollow aluminum window of 6 + 12A + 6 (mm). [ABSTRACT FROM AUTHOR]

Prefabricated buildings have the advantages of high efficiency and saving resources. However, China's prefabricated buildings were built relatively late, and there are problems in terms of their low standardization, integration, and industrialization. The purpose of this study was to evaluate the risk of constructing prefabricated buildings under the engineering, procurement, and construction (EPC) general contracting mode from the perspective of general contractors and to propose countermeasures for the key risks. Firstly, a risk evaluation index system was established via a literature analysis, and a questionnaire survey was used to collect the data. SPSS was used to conduct the data factor analysis to finally identify 4 first-level indicators and 14 second-level indicators. Then, a structural equation model (SEM) was developed to further evaluate the impact of each indicator on the risk of constructing prefabricated buildings under the EPC general contracting mode. The results showed that the construction and design risk had the greatest impact. Among them, the technical level of the construction personnel while conducting the hoisting, stacking, and protection of on-site materials and the lack of integrated design experience among the designers were the key points for risk control. On the one hand, this study explored the whole life cycle of a project, which makes up for the lack of risk analyses and the control being limited to a single engineering stage that has been presented in previous studies. On the other hand, in terms of the design, procurement, and construction as a whole research object, we found that the fuzzy evaluation method and analytic hierarchy process (AHP) used in previous risk analyses and evaluation methods have defects. They cannot verify the rationality of the logical relationship between the evaluation indices. In contrast, this study used the SEM method to fill this research gap. This ensures the scientific nature of our research to the greatest extent. Additionally, we also found some problems with this type of research: the selection of the evaluation indicators and data collection vary with the region, project characteristics, project contracting mode, and risk management subject, which influence the results of studies. Overall, the SEM method established in this study provides a reference and can help us conduct similar research and model evaluations in other regions. This method can guide project implementers to make the best risk-management decisions, so it is of great significance for practitioners in this field. [ABSTRACT FROM AUTHOR]